Apparatus for dressing crude asbestos separated from the source rock



Feb. 18, 1969 K. A. OESTERHELD 3,428,265 APPARATUS FOR DRESSING CRUDEASBESTOS SEPARATED FROM THE SOURCE ROOK Filed Aug. 25, 1966 KARL 05srem/51.0

ATTYK,

Feb. 18, 1969 K. A. OESTERHELD 3,428,265

APPARATUS FOR DRESSING CRUDE ASBESTOS SEPARATED'FROM THE SOURCE ROCKFiled Aug. 23, 1966 `Shee'c of2 ff u 'MV/,QWLLM- ,a y 9 ,47 57 f4 j 'gfl@ n i@ l' T l0 l f 5% /f\ @fg U4@ j 44 @y T l i 45 @(5 CJ-* Tl? @5" 55|4;/ V

| I lgl/ 4 .5l

i 'Hm 3 @2 /3 @il U I @53255 g 5% g i 5l 33 .32 1 f 1 mm Willi;

I* i 75W 53 W l 74% y yf WM 6 I /NrfNra/P 70 KARL A. OEsrfAPr/ELD Blfqww United States Patent O U.s. Cl. 241-259 1m. cl. Boze 13/26, 25/009 Claims This invention relates to an apparatus for dressing crudeasbestos separated from the source rock and is a continuation-in-part ofthe divisional application, Ser. No. 413,665, tiled Sept. 9, 1964, nowPatent No. 3,286,940, and embodies improvements in the art thereover.

In my U.S. Patent 3,170,834 a method of opening up fibrous bundles ofcrude asbestos separated from the source rock is described which enablesthe fibers hanging firmly together in bundles to be opened up to such adegree of perfection while maintaining the natural length of the iibersand without damaging the structure of the bers that was not attainablewith the previously known dressing methods and apparatuses used inpractice. This success is based on the fact that the crude asbestosmaterial suspended in a liquid is forced by means of a pump withcontrollable hydraulic pressure between the inner wall of a housing andthe surface of a motor-driven shaft or a rotor mounted on the shaftalong rigid friction surfaces and elastically yielding counterfrictionsurfaces over a long helical path having a length amounting to amultiple of the length of the iibers and during this operation thefibres are subjected to friction and continuously bent to and fro inconstantly varying directions. The frictional effect and bending effectcausing the fibers to be completely opened up can be realized by variousapparatuses of appropriate construction, e.g. by the apparatus shown anddescribed in my pending U.S. patent application Ser. No. 413,665, whichapparatus consists of a conical housing and a conical rotor rotatablymounted in the housing and formed of a plurality of annular rubber disksiiXed on a motor-driven shaft.

Practice has shown that the kinds of asbestos varying considerablyaccording to the place of their origin must be subjected in each case toa particular individual treatment when itis intended to achieve the bestpossible degree of dressing the iibers while meeting at the same timethe requirements that the natural length of the fibers should bemaintained and the fibers should not be damaged. By controlling thehydraulic pressure with which the fiber-liquid mixture is forced by thefeed pump through the dressing apparatus between the rigid frictionsurfaces and the elastically yielding counterfriction surfaces and/or byvarying the speed of the shaft rotatably mounted in the housing, it isnot possible to regulate the operation of the dressing apparatus in afully satisfactory manner. A third possibility of influencing theoperation of the dressing apparatus consists in varying the elasticcompressibility of the elastically yielding counterfriction surfacecooperating with the rigid friction surface in accordance with therespective requirements.

It is the object of the present invention to construct the elasticcounterfriction surface in such a Way that a change of its elasticcompressibility can be effected with 3,428,265 Patented Feb. 18, 1969ice simple means and in a convenient manner and performed any timeduring the operation of the dressing apparatus.

This object is achieved according to the invention in that a housing ofthe dressing apparatus accommodates a lining of elastically yieldingmaterial which is inflatable with compressed air and in its fullyinflated condition engages closely the surface of a shaft or of a rotormounted on the shaft and a regulating member is rfitted in acompressed-air pipe subjecting the lining to the action of compressedair, the operation of which regulating member permits the bearingpressure of the lining against the shaft or the rotor to be adjusted insuch a manner that it ensures, in conjunction with the hydraulic feedpressure and with the speed of the shaft, the frictional effect and theintensity of bending necessary for completely opening up the fibrousbundles.

The apparatus for dressing fibers as proposed by the present inventionmay be used equally well for all kinds of asbestos because the elasticcompressibility of the inflatable lining can be very accuratelyregulated. It saves the purchase and provision of a plurality ofapparatuses which can be used only for opening up crude asbestos havingparticular properties, such as, e.g. short-fibered, medium-bered orlong-iibered crude asbestos, or for asbestos material with a definitethickness of the individual iibers. The arrangement of the inatablelining provides the advantageous possibility of bringing the elasticcountcrfriction surface into engagement with the motordriven shaftexpediently equipped with one or several helical liat ribs or with therotor mounted on the shaft by increasing the internal pressure andwithout leaving a gap between the engaging parts, after previously theregular passage of the ber-liquid mixture in a helical iiow has beeninitiated with the lining iirst inliated to a slight degree only andconsequently lifted slightly off the shaft or the rotor.

The inflatable elastic lining, in case it is heavily worn after a longperiod of use, can be replaced in a simple manner by a new liningwithout excessively high costs and without the dressing apparatusbecoming unserviceable for a longer period of time.

The .rotor co-operating as a rigid rotating friction surface with theinflatable lining acting as elastically yielding counterfriction surfacemay be of solid construction or constructed as a hollow body incylindrical form or in the form of a truncated cone. The inner Wallsurface of the inflatable lining must in any case be such that thelining in its inflated condition tightly encloses the rotor at leastwith a section of its inner wall surface.

In some kinds of asbestos the best degree of opening up the fibers isachieved when the fibrous bundles are first subjected to .a less heavyrubbing and bending action and subsequently submitted to an intensifiedafter-treatment. To be able to carry out also such manner of treatmentwith the dressing apparatus as proposed by the invention, the inventionfurther suggests to arrange a packet of annular disks in the housing onthe downstream side of the inflatable lining surrounding the shaftequipped with one or several helical flat ribs, which packet of annulardisks is composed of rigid annular disks with a bore diameter greaterthan the diameter of the shaft and yieldable annular disks of elasticmaterial, such as, e.g rubber, with a bore diameter equal orapproximately equal to the diameter of the shaft, the rigid annulardisks being arranged so as to alternate with the yieldable annular disksthereby to form annular chambers.

The bearing pressure of the annular rubber disks against the shaft canbe varied in a range which is, however, not very wide by tightening to amore or less great extent screws which connect a cover of the housing tothe body of the housing, thus increasing or reducing the pressureexerted by the cover on the annular disks of the packet of annulardisks, whereby an appropriate bearing pressure of the annular rubberdisks against the shaft is obtained. In this case it is, of course, notpossible to regulate the bearing pressure as accurately as in the caseof the elastically yielding inflatable lining, but this is not necessaryfor the intensified after-treatment of the asbestos fibers which are inpart already opened up by the inflatable lining.

Two embodiments of the invention will now be described by way of exampleand with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic longitudinal section through a first embodimentof the dressing apparatus according to the invention having aninfiatable lining directly enclosing the motor-driven shaft and furtherhaving a second functional part for the intensified after-treatment ofthe fibers arranged on the downstream side of the lining;

FIGS. 2 and 3 are diagrammatic side elevational views, on a reducedscale, of component parts of the apparatus of FIG. 1;

FIG. 4 is a diagrammatic view of a plant in which the fiber-liquidmixture is circulated several times through the dressing apparatus ofFIG. 1, and

FIG. 5 is a diagrammatic longitudinal section through a secondembodiment of the dressing apparatus having an elastically yieldinginflatable lining which encloses a conical rotor.

In all the figures all similar or similarly acting parts are designatedby the same reference numerals.

In FIG. 1, reference numeral 1 designates a horizontally arrangedelongated housing of a dressing apparatus which has on the left-handside of this gure a rigid end wall 2 and is closed on the right-handside by a screwed- `on-cover 3. In a central bore 4 in the end wall 2 arigid shaft 5 is rotatably mounted which extends through the entirelength of the housing 1. As shown in FIG. 4, the end of the shaft 5projecting beyond the end wall 2 is connected to an electric motor 7through the intermediary of a variable intermediate gear 6 and can bedriven at an adjustable speed. The other end of the shaft passes througha central bearing bore 8 in the cover 3. Longitudinal channels 9 areformed in the bearing bore 8 for the discharge of the fiber-liquidmixture from the dress- A ing apparatus.

Behind the end wall 2 (FIG. l) there is an annular chamber 10 which isopen towards the shaft 5. This annular chamber 10 communicates with acontainer 13 (FIG. 4) by means of a connecting piece 11 and a pipeconduit 12 connected thereto, which container 13 accommodates asbestosmaterial to be dressed mixed with water or any other suitable liquid. Inthe pipe conduit 12 a feed pump 14 is arranged which feeds, in thearrowed direction, the asbestos material suspended in liquid into theannular chamber 10 under high pressure.

Between two partition walls 15 and 16, of which the partition wall 15shown on the left of FIG. l and extending at an incline to the shaft 5forms part of the wall surrounding the annular chamber 10, there is aspace 17 for receiving an inata-ble hollow body 18 of annularcross-section and made from rubber or rubberlike material. The annularhollow body 18 is inflated by means of a connecting piece 19 passingthrough the wall of the housing 1 and fitted with a manually regulablecheck valve (not shown in FIGS. 1 and 4 of the drawings), to such anextent that the cylindrical inner wall of the annular hollow body 18bears tightly against the shaft 5. The inflation pressure must be soadapted to the i pressure produced by the feed pump 14 that the latteris capable of forcing the fiber-liquid mixture slowly between thecylindrical inner wall of the annular hollow body 18 and the shaft 5 inthe direction towards the other end of the shaft thereby pushing backthe elastically yieldable cylindrical inner wall of the infiated annularhollow body 18.

As the shaft 5 rotates during this operation, the fiber bundles passingbetween the shaft 5 and the elastically yieldable hollow body 18 aredivided up into separate fibers in a gentle manner by friction and theindividual separated fibers are continually bent to and fro on thesurface of the shaft 5 as they continue to pass through the narrow gapbetween the cylindrical inner wall of the annular hollow body 18 and theshaft 5.

The bending movement is caused by the fact that the cylindrical innerwall of the annular hollow body 18, under the influence of the feedpressure, is not lifted continually the same distance from the shaft Sat all points of its cylindrical surface but is pressed-in more stronglyat some places than at others, whereby the strongly pressed-in placeschange continually. As a result, the fibers are alternately subjected tothe feed pressure moving them along the shaft 5 and to the peripheralforce of the revolving shaft 5 acting transversely to the longitu-dinaldirection of the shaft, so that the fibers are continually turned andtwisted during the rotary movement of the shaft and thereby continuallybent to and fro over their entire length in constantly varyingdirections.

In the example illustrated in FIG. 1, the apparatus is equipped not onlywith dressing or working elements as described above in a firstfunctional part but also with working elements by which the rigid shaft5 also cooperates with elastically yieldable counter pressure elementsarranged in a second functional part. This second functional part isseparated from the first functional part by the partition wall 16removably fitted in the housing 1 and surrounding the shaft S withclearance. Between the partition wall 16 and the cover 3 screwed on tothe housing 1 a packet of annular disks 20, 21 is clamped. This packetconsists of alternately arranged rubber disks 20, the bore diameter ofwhich is so dimensioned that these disks fit closely around the shaft 5or extend up to the shaft leaving only a small annular slit up againstthe shaft, and of rigid annular disks 21 made, for example, of metal andhaving a bore diameter which is considerably larger than the diameter ofthe shaft, so that annular spaces or chambers 22 are formed betweenthese annular disks 21 and the shaft 5. The vannular disks and 21 arenot axially shiftable in the housing 1 by means of the screwed-0n cover3 and secured against rotation in that they are provided, as shown inFIGS. 2 and 3, with noses 20 and 21', respectively, which project fromtheir periphery and are slipped into a longitudinal groove 23 in theinner wall surface of the housing 1 (FIG. 1).

The fiber-liquid mixture passing through the central bore in thepartition wall 16 into the second functional part of the dressingapparatus is forced through the small annular slit of the rst rubberdisk 20, whereby the fibers are subject to strong friction. On enteringthe annular charnber 22 adjoining the first rubber disk 20, the fibersturning upwards are bent and relieved in the annular chamber 22. Thefiber-liquid mixture pressing forward conveys the fibers with the liquidsurrounding them past the next rubber disk 20 into the annular chamber22 following it, whereby the fibers are again subjected to strongfriction and on entering the next annular chamber 22 are bent. Thisprocedure is repeated at each successive rubber disk 20 and annularchamber 22.

The fiber-liquid mixture is forced out of the last annular chamber 22through the already mentioned channels 9 in the bearing bore 8 in thecover 3 into a pipe conduit 24 (FIG. 4) in which it is conveyed to afurther treatment stage, for example, a drying place, or is returnedthrough a two-way cock 25 arranged in the pipe conduit 24 and a branchconduit 26 into the container 13 from which the fiber-liquid mixture isagain forced into the dressing apparatus by the feed pump 14. Thus thefiber-liquid mixture can be fed once or in repeated circulation throughthe dressing apparatus until the liber bundles are completely loosenedup in the desired manner.

As indicated in dot and dash lines in FIG. 1, the shaft 5 can have oneor several ribs 27 extending in a helical line and assisting in bendingthe fibers to and fro when the latter slide over the ribs in theirforward movement under the feed pressure.

When a kind of asbestos material is concerned in which the individualfibers do not stick together too tightly or are very sensitive, it isrecommendable to use only that functional part of the dressing apparatuswhich has the inflatable hollow body inserted therein. For this purposeeither the annular disks 20 and 21 may be removed from the housing 1 ora dressing apparatus may be used which has only the inilatable hollowbody 18 inserted therein. In each case the hollow body 18 will beinflated only to a slight extent at the commencement of the opening-upoperation in order to rst initiate the helical circulating movement ofthe liber-liquid mixture in the apparatus and subsequently, by operatingthe regulating member in the compressed-air pipe leading to the hollowbody 18, the internal pressure in the hollow body and consequently thebearing pressure of the cylindrical inner wall of the hollow body 18against the shaft 5 can be so adjusted to the hydraulic pressure withwhich the fiber-liquid mixture is conveyed by the feed pump 14 throughthe dressing apparatus and to the speed of the shaft 5 that the fibersof the crude asbestos material will be completely separated from oneanother but not shortened and not damaged in their structure.

The operation of the second functional part of the dressing apparatuscontaining the rigid annular disks 21 and the annular rubber disks 20can be adjusted only to a limited extent by tightening more or lessstrongly nuts 28 on bolts 29 connecting the cover 3 with the housing 1.This causes the walls 30 of the holes in the annular rubber disks 20 tobe pressed more or less strongly against the shaft 5.

For the proper function of the dressing apparatus it is immaterialwhether it is provided with a horizontal shaft as shown in FIG. l r withan upright shaft.

FIG. shows an apparatus for dressing crude asbestos which has avertically disposed shaft 5 rotatably mounted in two bearings 31. Thebearings 31 are mounted by means of lateral trestles 32 to I-rails 33 ofa supporting structure. The shaft 5 is driven through the intermediaryof a belt pulley 34 only part of which is shown in the drawing and whichis connected to a variable speed gear of known construction (not shown).Arranged on the free end of the shaft 5 is a rotor 35 consisting of ametallic hollow body and secured to the shaft 5 by a headpiece 36 ofhardened steel. The headpiece 36 is screwed with a threaded shank 36into a central tapped hole in the shaft 5 and presses by means of aninterposed sleeve 37 in axial direction against the body of the rotor3S, so that a hub 38 of an annular disk 39 to which the rotor 35 isfastened by means of screws and which forms the end wall at the broaderbase of the conical hollow body, bears heavily against a shoulder 5 onthe shaft 5.

The rotor 35 is surrounded by a housing. The housing consists of atwo-part cylindrical wall, the one part 40 of which has a substantiallygreater wall thickness than the other part 41. To the two ends of thepart 40 of the wall of the housing flanges 42 and 43 are welded. Anannular disk 47 is fastened to the upper flange 42 in FIG. 5 by screwbolts44 and nuts 45 with the interposition of spacers 46 supporting theannular disk, which disk forms the upper end wall of the housing.Connected to the flange 43 of the part 40 of the wall also by screwbolts 44 surrounded by spacers 46 and nuts 45 is a counterllange 48which is welded to the part 41 of the cylindrical wall of the housingwhich is of smaller wall thickness and has an end wall 41 firmlyconnected thereto by welding. A hub 49 xed in a central bore in the endwall 41 of the housing by welding serves for the reception of astuingebox packing 50 composed of a plurality of rings consisting oftallow cords or the like. The section of the shaft 5 positioned in theregion 0f the stuling-box packing 50 is provided with a bushing 51protecting this section of the shaft.

Arranged in front of the stuffing-box packing 50 are a sleeve 52 and apacking gland 53, the latter being provided with an outer flange 53which is connected by screw bolts 54 and nuts 55 to a counterflange 49on the hub 49. By tightening the bolt nuts 5S 'the packing gland 53permits in a known manner to readjust the `stuffingbox packing 50 whenthe passage for the shaft in the stulingdbox packing is no longerentirely leakproof.

The relatively large free annular space between the conical outer wallsurface of the rotor 35 and the cylindrical inner surface of the part 40of the cylindrical wall of the housing is lled by a thick-walled rubberlining 56. The rubber lining is so shaped at its two ends as to formradially projecting collars 56. The collar 56 situated at the upper endof the lining 56 in FIG. 5 engages in a recess 57 on the inner side ofthe end wall 47 and in a recess 58 in the end face of the part 40 of theWall of the housing and is tightly clamped between the end wall 47 andthe part 40 of the cylindrical wall of the housing. Similarly, thecollar 56' at the other end of the rubber lining 56 is held in recesses58 and 57 in the lower end wall of the part 40 of the cylindrical wallof the housing and in the flange 48 so as to be non-rotat able andaxially and radially unshiftabl-e. In this example the rubber lining 56is additionally secured against axial and radial shifting by a flange 59on the inner side of the part -40 of the cylindrical wall of the housingand by an internal extension of the flange 48.

The outer wall surface of the rubber lining 56 between the end collars56 is freely spaced from the inner wall surface of the part 40 of thecylindrical wall and denes, together with this part 40, an elongatednarrow annular space 60. The annular space 60 communicates with acompressed-air pipe 61 which is connected to a bore formed in thecentral region -of the part 40 of the wall of the housing. Thecompressed-air pipe 61 extends from a compressed-air source, e.g. froman air compressor 62, and a manually operable regulating member 63 whichis constructed as a check valve is iitted in the compressedair pipe 61,the operation of which regulating member permits the air pressure actingon the rubber lining 56 to be regulated as desired.

In FIG. 5 the rubber lining 56 is shown in a condition in which it isnot yet subject to the action of compressed air. In this case -a section64 of the inner wall surface 64 of the rubber lining 56 which is ofconical shape to conform to the conicalness of the outer wall surface ofthe rotor 35 is positioned opposite to the outer wall surface of therotor 35 at a free distance therefrom. The narrow conical annular gap xfacilitates setting the dressing apparatus going in so far as not toogreat a resistance counteracts the stream of the liber-liquid rnixture.As soon as the liber-liquid mixture is imparted the desired flowcorresponding t0 a helical course, compressed air is admitted into theannular space 60. This causes the rubber lining 56 to be curved inwardlyand to be pressed with the conical section 64' of its inner wall surfaceagainst the outer wall surface of the rotor 35 without leaving a gap.Regulating the amount of the cornpressed air acting on the rubber lining56 permits the bearing pressure of the lining against the rotor 35 to bevaried as desired and to be regulated in such a manner as is required inview of the hydraulic pressure with which the liber-liquid mixture isforced by the pump 14 through the dressing apparatus and in view of thespeed of the shaft 5 required to open up the crude asbestos material inthe best possible manner.

The fiber-liquid mixture is, in a Vsimilar manner as in the dressingapparatus according to FIG l, sucked by the motor-driven feed pump 14out of a storage container 13 and conveyed through the pipe conduit 12which is connected by a lianged joining piece 90` to a connection piece91 welded to the upper end wall 47 of the housing and provided with aflange 91', into the dressing apparatus at the upper end thereof. Afterthe fiber-liquid mixture has been forced through between the conicalinner wall surface of the rubber lining 56 blown up inwardly bycompressed air and the conical outer wall surface of the rotor 35rotated by the shaft 5, it passes into a chamber 84 of the housingconstituted by the parts 47, 40, 41 and 41', which chamber is situatedbelow the great base circle of the conical rotor 35 closed by theannular disk 39. The fiber-liquid mixture then leaves the chamber 84through a lateral connection piece 65 on the housing to flow eitherthrough the pipe conduit 24 to a further processing station or throughthe two-way cock 25 and the pipe conduit 26 back to the storagecontainer 13.

The conical section 64' of the inner wall surface of the rubber lining56, which constitutes the lworking surface of the rubber lining, issubjected during the operation of the dressing apparatus to unavoidableabrasion wear. Therefore, a device is provided by means of which theshaft can be readjusted in axial direction in accordance with therespective degree of wear of the rubber lining.

rPhe readjusting device consists of a threaded spindle 66 which isscrewed into a tapped hole in a plate 67. The plate 67 is welded to aplate 68 disposed perpendicularly to the plate 67 and having alongitudinal rib 68', which plate 68 in turn is screwed to a platte 69welded to a rail 33 of the supporting structure. A handwheel 70 is fixedand a locking lever 71 screwed on the free end of the spindle 66. When,by operating the handwheel 70, the shaft 5 has been brought into aposition in which the conical section 64' of the inner wall surface 64of the rubber lining 56 not yet acted upon by compressed air has theproper spacing from the outer wall surface of the conical rotor 35, thelocking lever 71 is screwed upwardly against the plate 67 and therebythe shaft 5 locked in its adjusted position.

The threaded spindle 66 is connected to the shaft 5 by a ring 72 whichis fixed on the lower end of the shaft 5 by a cylindrical head screw 73.Accommodated in an enlarged section of the bore in the connecting ring72 are the outer edges of the two races of a thrust ball bearing 74 andthe outer edge of a stepped spacer 75 `by means of which the ballbearing 74 is supported against a shoulder 66' on the threaded spindle66. A castle nut 76 screwed on the upper threaded section of the spindle66 of reduced diameter holds, with the aid of an annular disk 77, ytheball bearing 74 and the spacer 75 in position on the spindle 66 so thatthey are axially unshiftable. Formed in the enlarged section of the borein the connecting ring 72 in a place below the radially projectingportion of the spacer 75 is an annular groove in which a spring ring 78is inserted which fixes the ball bearing 74 and the spacer 75 on theconnecting ring 72.

The lower half of the connecting ring 72 is surrounded by a cylindricalhousing 79 which is welded to the plate 67 and to the longitudinal rib68 of the plate 68. A felt sealing ring 80 inserted in the housing 79prevents dirt and moisture from getting to the pants of the adjustingdevice mounted within the connecting ring 72.

For limiting the axial adjustability of the shaft 5, two slide rings 81are arranged on the shaft which bear against different sides of the twobearings 31. Each slide ring 81 has an opening 82 which is in the formof an oblong hole and in which the cylindrical head 83 of a cylindricalhead screw 83 screwed into the shaft is positioned. When the head 83 ofthe cylindrical head screw 83 butts against the one end or the other endof the opening 82 in the slide ring 81, the shaft 5 has reached duringits adjusting movement its extremely advanced position or its extremelyretracted position.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive.

I claim:

1. An apparatus for dressing crude asbestos separated from the sourcerock and being in the form of fibrous bundles suspended in a liquid,comprising a housing, an inlet on said housing lfor admitting thefiber-liquid mixture into said housing, an outlet on said housing fordischarging the fiber-liquid mixture from said housing, a motor-drivenshaft rotatably mounted within said housing, a rigid working surface onsaid shaft, a lining of elastically yielding material inflatable withcompressed air in said housing lixedly held on the wall of said housingand closely engaging said Working surface on said shaft when in fullyinliated condition, a regulable feed pump for forcing with acontrollable hydraulic pressure the fiber-liquid -mixture admittedthrough said inlet into said housing in a circulating liow between saidrigid working surface on said shaft and a counterfriction surface ofsaid lining while subjecting the fibers to friction and continuouslybending them in constantly varying directions, and for conveying thefiber-liquid mixture to said outlet on said housing, a compressed-airpipe for subjecting said lining to the action of compressed air, and aregulating member fitted in said compressed-air pipe and permitting,when operated, the bearing pressure of said lining surrounding saidworking surface on said shaft to be adjusted to the frictional effectand the intensity of bending the fibers which result in completelyopening up the fibers.

2. An apparatus as claimed in claim 1, wherein rigid working surface onthe shaft is constituted by surface of the shaft.

3. An apparatus as claimed in claim 1, wherein rigid working surface onthe shaft is constituted by outer wall surface of a rotor which ismounted on shaft.

4. An apparatus as claimed in claim 1, wherein inliatable liningconsists of rubber.

5. An apparatus as claimed in claim 2, wherein the housing iscylindrical, a removable partition wall is provided in the housing theinflatable lining is in the form of an annular tube and is inserted inthe housing so as to engage with its outer wall surface the innersurface of the wall of the cylindrical housing and a connecting piece isprovided on the inflatable lining for the connection of thecompressed-air pipe, which connecting piece extends through a bore inthe wall of the housing.

6. An apparatus as claimed in claim 5, wherein at least one helical atrib is provided on the shaft, the infiatable lining in the form of anannular tube surrounds the shaft with a smooth inner wall surface, apacket of annular disks is arranged in the housing on the downstreamside of the inflatable lining, the packet of annular disks is composedof rigid annular disks with a bore diameter greater than the diameter ofthe shaft and yieldable annular disks of elastic material with a borediameter approximately equal to the diameter of the shaft, the rigidannular disks are arranged so as to alternate with the yieldable annulardisks thereby to form annular chambers, a cover closes the housing onone side and presses against the packet of annular disks, screw boltsare provided to connect the cover to the housing and nuts are screwed onthe screw bolts and permit the bearing pressure of the walls of theholes in the yieldable annular disks against the shaft to be regulatedby appropriately tightening the nuts on the screw bolts.

7. An apparatus as claimed in claim 6, wherein the yieldable annulardisks consist of rubber.

8. An apparatus as claimed in claim 3, wherein the inflatable lining isin the form of a thick-walled solid annular body with collars at bothends, the housing has the the the the the the a cylindrical wallcomposed to two wall sections of different wall thicknesses, two flangesare formed on the two ends of the wall section of increased wallthickness, one flange is formed on the wall section of smaller wallthickness which forms an extension of the wall section of increased wallthickness and two end walls close the housing at the two ends thereof,the inflatable lining being clamped with its end collars within thesection of the cylindrical wall of the housing of increased wallthickness between the iiange on the one end of the wall section ofincreased wall thickness and the end wall at one end of the housing andbetween the flange on the other end of the wall section of increasedwall thickness and the flange on the wall section of smaller wallthickness.

A9. An apparatus as claimed in claim v8, wherein the rotor has a conicalouter surface and only a section of the smooth inner wall surface of theinflatable lining inserted in the housing is of conical shape to conformto the conical outer surface of the rotor surrounded by the lining.

References Cited UNITED STATES PATENTS 3,286,938 11/1966 Moore et al.241--259 X HOWARD R. CAINE, Primary Examiner.

U.S. Cl. XR.

1. AN APPARATUS FOR DRESSING CRUDE ASBESTOS SEPARATED FROM THE SOURCEROCK AND BEING IN THE FORM OF FIBROUS BUNDLES SUSPENDED IN A LIQUID,COMPRISING A HOUSING, AN INLET ON SAID HOUSING FOR ADMITTING THEFIBER-LIQUID MIXTURE INTO SAID HOUSING, AN OUTLET ON SAID HOUSING FORDISCHARGING THE FIBER-LIQUID MIXTURE FROM SAID HOUSING, A MOTOR-DRIVENSHAFT ROTATABLY MOUNTED WITHIN SAID HOUSING, A RIGID WORKING SURFACE ONSAID SHAFT, A LINING OF ELASTICALLY YIELDING MATERIAL INFLATABLE WITHCOMPRESSED AIR IN SAID HOUSING FIXEDLY HELD ON THE WALL OF SAID HOUSINGAND CLOSELY ENGAGING SAID WORKING SURFACE ON SAID SHAFT WHEN IN FULLYINFLATED CONDITION, A REGULABLE FEED PUMP FOR FORCING WITH ACONTROLLABLE HYDRAULIC PRESSURE THE FIBER-LIQUID MIXTURE ADMITTEDTHROUGH SAID INLET INTO SAID HOUSING IN A CIRCULATING FLOW BETWEEN SAIDRIGID WORKING SURFACE ON SAID SHAFT AND COUNTERFRICTION SURFACE OF SAIDLINING WHILE SUBJECTING THE FIBERS TO FRICTION AND CONTINUOUSLY BENDINGTHEM IN CONSTANTLY VARYING DIRECTIONS, AND FOR CONVEYING THEFIBER-LIQUID MIXTURE TO SAID OUTLET ON SAID HOUSING, A COMPRESSED-AIRPIPE FOR SUBJECTING SAID LINING TO THE ACTION OF COMPRESSED AIR, AND AREGULATING MEMBER FITTED IN SAID COMPRESSED-AIR PIPE AND PERMITTING,WHEN OPERATED, THE BEARING PRESSURE OF SAID LINING SURROUNDING SAIDWORKING SURFACE ON SAID SHAFT TO BE ADJUSTED TO THE FRICTIONAL EFFECTAND THE INTENSITY OF BENDING THE FIBERS WHICH RESULT IN COMPLETELYOPENING UP THE FIBERS.